This invention relates to a pedal device used for playing of a drum such as a bass drum.
As disclosed in Japanese Patent Application Publication No. 2007-017805, a pedal device of this kind includes a base plate, a pedal, a chain, a rotary shaft, a beater, a tension coil spring, and others. Columns in a pair extend upward from the front end of the base plate. The rotary shaft is rotationally supported on the respective upper ends of the columns in a pair. The beater and a wheel are attached to the center of the rotary shaft. The pedal is rotationally attached to the rear end of the base plate. One end of the chain is coupled to the rotary shaft while being wound around the wheel. The opposite end of the chain is coupled to a free end of the pedal. The upper end of the tension coil spring is coupled through a coupling ring to a crank arm attached to an end portion of the rotary shaft. The lower end of the tension coil spring is coupled to the upper end of the bolt that adjusts the tension of the tension coil spring. The bolt is fixed to a bracket projecting from one of the columns with an upper nut and a lower nut in a pair. When the pedal is depressed against the biasing force of the tension coil spring, the beater is rotated by the chain, the wheel, and the rotary shaft to beat a bass drum. When the pedal is released from the depression, the biasing force of the tension coil spring makes the beater and the pedal return to their initial positions.
As shown in FIG. 10, when a player operates a pedal to rotate a beater 100 back and forth, a tension coil spring 101 pivots back and forth about the lower end of the tension coil spring 101, which is a fulcrum coupled to a bolt 102. At this time, if the tension coil spring 101 swings back and forth, if the pivot angle A101 of the tension coil spring 101 is increased, the force P of a horizontal component acting on a swinging fulcrum F101 is also increased. This makes the entire pedal device swing back and forth easily together with the pivot motion of the tension coil spring 101, thereby reducing the operability of the pedal. The large backward and forward swinging motion of the tension coil spring 101 also increases the force of friction between the lower end of the tension coil spring 101 and the bolt 102. This increase in the force of friction between the tension coil spring 101 and the bolt 102 reduces smooth movement of the pedal and further reduces the operability of the pedal.